Electrical property of pyrolyzed polypyrrolone film at high temperature

Insulating polypyrrolone (pyromellitic dianhydride-3,3′-diaminobenzidine (PMDA-DAB)) film can be converted into an electrical conductor by pyrolysis at high temperature in nitrogen atmosphere. The conductivity of pyrolyzed PMDA-DAB film at room temperature was measured as a function of pyrolysis temperature and time. A maximum room-temperature conductivity as high as 700 S/cm for PMDA-DAB film pyrolyzed at 1200°C for 1 h was obtained, and it was very stable in air. The current-voltage curve for PMDA-DAB film pyrolyzed in the range 700–1200 °C coincides with Ohmʹs law. The temperature dependence of conductivity of pyrolyzed PMDA-DAB film can be expressed by a three-dimensional variable-range hopping (VRH) model, and the hopping energy (T0) of charge carriers decreases with increase of pyrolysis temperature.